I think those proprietary, enterprise features are massively overstated. Push email isn't so new now, and iOS and Android are quickly closing the gap on enterprise features, including device management, remote wipe, VPN etc.

Just like Microsoft, BlackBerry has and will continue to have lots of loyal customers. That's not enough to grow a company, though, and having started out in the consumer market, Android and iOS now have a huge advantage in the enterprise since employees are asking to bring their own device to work.